Diagnostic Procedure
WARNING: This page is about a different car, the 2002 Toyota Land Cruiser, 2002 Lexus LX 470, 2001 Toyota Land Cruiser, and 2001 Lexus LX 470. However, it is still accessible from the selected car via links, so may be relevant.
Remove and inspect operation of solenoid. See SL SOLENOID under COMPONENT TESTS. If solenoid is okay, inspect valve body and/or torque converter. See appropriate OVERHAUL article.